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FM放送とマルチパスを適応フィルタで極めてみた / Solving multipath dis...
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Kenji Rikitake
January 16, 2020
Technology
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3.4k
FM放送とマルチパスを適応フィルタで極めてみた / Solving multipath distortion of FM broadcast by adaptive filters
さくらの夕べ 研究所ナイト 2020年1月16日 発表原稿
Kenji Rikitake
January 16, 2020
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Transcript
FM์ૹͱϚϧνύεΛ దԠϑΟϧλͰۃΊͯΈͨ Kenji Rikitake / Sakura Lab Night 16-JAN-2020 1
Kenji Rikitake Γ͖͚ͨ ͚Μ͡ ྗ ݈࣍ 16-JAN-2020 ͘͞Βͷ༦ ݚڀॴφΠτ Sakura
Internet Fukuoka Office Fukuoka City, Fukuoka, Japan @jj1bdx Kenji Rikitake / Sakura Lab Night 16-JAN-2020 2
ٕज़࢜ʢใֶ෦ʣ ྗ݈ٕ࣍ज़࢜ࣄॴ ॴ ϖύϘݚڀॴ ٬һݚڀһ ΞϚνϡΞແઢྺ 44 Kenji Rikitake /
Sakura Lab Night 16-JAN-2020 3
FM์ૹϚϧνύεׯবͰԻ͕Ԛ͘ͳΔ • ෳܦ࿏ͷࣹ͕߹͞Εͯܗ͕ཚΕΔ • ৼ෯Ұఆͷ͕ͣৼ෯͕มԽ͢Δ • ৼ෯ͷมԽଈࠁҐ૬ͷΈ • Ґ૬͕ΉͱͱͯෆշͳԻ͕͢Δ Kenji
Rikitake / Sakura Lab Night 16-JAN-2020 4
Kenji Rikitake / Sakura Lab Night 16-JAN-2020 5
͍͚ͬͯͳ͍͜ͱ ৼ෯Ұఆʹڧ੍ͯ͠Έফ͑ͳ͍! Ϧϛολແҙຯ Kenji Rikitake / Sakura Lab Night 16-JAN-2020
6
ݪཧʹ࣮ʹߟ͑Δ ෳͷԆ৴߸͕ׯব͍ͯ͠ΔͷͰ͋Εɺ ͦͷׯবͷٯԋࢉΛߦͬͯऔΓআ͘ Kenji Rikitake / Sakura Lab Night 16-JAN-2020
7
Kenji Rikitake / Sakura Lab Night 16-JAN-2020 8
Kenji Rikitake / Sakura Lab Night 16-JAN-2020 9
ϚϧνύεׯবҎલͷঢ়ଶʹ͢ʹ • ԆͱՃࢉFIRϑΟϧλͰ࣮ݱͰ͖Δ • ࣹͷٯԋࢉΛΕΑ͍ • LMS๏ͰదԠϑΟϧλΛܾఆ • ͷܾఆ݅: ৼ෯Ұఆʹ͢
Kenji Rikitake / Sakura Lab Night 16-JAN-2020 10
దԠϑΟϧλͷ࣮ྫ 1980ʹจൃද 1 ྛًࢯʹΑΔFMDDC-3 ྗʹΑΔairspy-fmradion 1 ݄ ࢤ, Ӌௗ ޫढ़,
దԠσΟδλϧϑΟϧλʹΑΔFMϚϧνύεͻͣΈࣗಈআڈͷҰํࣜ, ςϨϏδϣϯֶձࢽ, 1985, 39 ר, 3 ߸, p. 228-234, ެ։ 2011/03/14, Online ISSN 1884-9652, Print ISSN 0386-6831, h>ps:/ /doi.org/ 10.3169/itej1978.39.228, h>ps:/ /www.jstage.jst.go.jp/arHcle/itej1978/39/3/39_3_228/_arHcle/-char/ja Kenji Rikitake / Sakura Lab Night 16-JAN-2020 11
దԠϑΟϧλΛVOLKͰ࠷దԽ • ίϯύΠϥʹͤΔͱݶք͕͋Δ • VOLK: SIMD໋ྩద༻ϥΠϒϥϦ h-p:/ /libvolk.org/ • ϧʔϓͰॲཧͰ͖ΔͷΛSIMDʹ͢Δ
• ੵԋࢉ6ഒͷߴԽ2 2 Kaby Lake, volk_32fc_x2_dot_prod_32fc(), generic -> u_avx_fma Kenji Rikitake / Sakura Lab Night 16-JAN-2020 12
#if !VOLK for (unsigned int i = 0; i <
m_filter_order; i++) { output += m_state[i] * m_coeff[i]; } #else // VOLK volk_32fc_x2_dot_prod_32fc(&output, m_state.data(), m_coeff.data(), m_filter_order); #endif // VOLK Kenji Rikitake / Sakura Lab Night 16-JAN-2020 13
ྗͷ࣮: airspy-fmradion Airspy HF+RTL-SDRͱMacRaspberry PiͷΈ߹ΘͤͰಈ࡞ ߴڃFMνϡʔφʹඖఢ FMԕڑड৴ʹޮՌ ઈࢍ։ൃத h"ps:/ /github.com/jj1bdx/airspy-fmradion
Kenji Rikitake / Sakura Lab Night 16-JAN-2020 14
Thank you Graphics credits: • Audacity simula.on: Kenji Rikitake •
Mul.path impulse response: I, Cantalamessa, h>ps:/ / commons.wikimedia.org/wiki/ File:Mul.path_impulse_response.png from Wikimedia Commons, licensed CC BY 2.5 Kenji Rikitake / Sakura Lab Night 16-JAN-2020 15